Providing a direct link between animal and human models of fear learning and extinction is vital to developing knowledge that can be translated to the treatment for human anxiety disorders. Although claims from previous studies in humans are largely consistent with animal models, these claims are limited for two reasons: 1. The paradigms used differed across species (i.e., visual vs. auditory conditioning). 2. Standard brain imaging techniques are limited in examining neural circuitry in humans. The proposed research will provide a more direct link by using auditory fear conditioning, a paradigm extensively studied in animals and by using technical advances in functional magnetic resonance imaging (fMRI). Crucial regions of the auditory fear circuit, the amygdala, auditory thalamus, auditory cortex and medial prefrontal cortex, as well as their subregions will be studied using event-related fMRI. Better understanding of cross-species analogies will be achieved by: 1. Using whole brain event-related fMRI investigating the neural circuitry underlying auditory fear conditioning and extinction in humans. 2. Using high-resolution fMRI to achieve insight into the involvement of subregions of the auditory fear circuit during fear learning and extinction in humans [unreadable] [unreadable]